This project seeks to construct, test and prepare for a later clinical trial by others a flying-spot infra-red (ER) or near IR transmission scanner, possibly useful as an adjunctive breast-cancer examination modality. The instrument differs from previous designs by this and other groups in that the mechanical translation of the object is avoided, in that a new input-output synchronization technique is introduced and in that the chosen configuration is capable of closely matching that of the well-accepted X-ray equipment with which the new device will be compared in later clinical trials; this feature should constitute a much more rational test of relative merit than has been possible with existing transilluminators. The advantages of the equipment are expected to be: (1) improved contrast (and secondarily resolution) thereby increasing diagnostic accuracy; (2) orthodiascopic (distortion-free) imaging; (3) digital output, facilitating multi-wavelength examinations and contrast enhancement; (4) full daylight operation; (5) sensitivity to chemical as well as physical composition, facilitating use of chemical contrast agents; and (6) no patient dose.